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Author Topic: ZERO NOISE technique  (Read 371823 times)

Ray

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ZERO NOISE technique
« Reply #80 on: July 08, 2007, 10:45:57 PM »

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oh I understand now. Your way to proceed is to bracket a couple of stops below and above the "correct" exposure. In my opinion bracketing underexposed as a rule is not necesarry. Any underexposed shot (and -3 is VERY underexposed) doesn't provide additional clean information to the 0 and +3 shots.

My concept here is slightly different: take one shot making sure that you capture all highlights, but not underexposing at all, just make sure you don't blow information (a RGB splitted camera histogram is good enough to check this). This is the most important shot of all and after it you can forget about any additional underexposed shot.
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I've spent several hours over the past few days comparing Jonathan's 'split top layer blending method' with 2, 3 and 4 RAW images of the same scene loaded into HDR

The 'split top layer' method using just 2 images does not need an underexposed image. The bottom layer should just be an image correctly exposed for the highlights, which usually means when converting in ACR, approximately a minus 1 stop EC adjustment should be applied to 'recover' highlights.

My initial impression was that I was still getting a hint of the halo effect, but I now believe this was due to traces of silicon sealant around the edges of the window panes and/or inappropriate adjustments with Photoshop's Shadow/Highlight tool.

What I have noticed is that HDR in PSCS2 is not able to recover highlights well. If the lowest exposure is a full exposure to the right, the highlights will be slightly blown. In order to avoid this, I think it's necessary to include an underexposed image when using HDR.

Loading 16 bit TIF conversions into HDR seems to produce some pretty awful results.
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Guillermo Luijk

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« Reply #81 on: July 09, 2007, 02:29:06 AM »

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I've spent several hours over the past few days comparing Jonathan's 'split top layer blending method' with 2, 3 and 4 RAW images of the same scene loaded into HDR

The 'split top layer' method using just 2 images does not need an underexposed image. The bottom layer should just be an image correctly exposed for the highlights, which usually means when converting in ACR, approximately a minus 1 stop EC adjustment should be applied to 'recover' highlights.

My initial impression was that I was still getting a hint of the halo effect, but I now believe this was due to traces of silicon sealant around the edges of the window panes and/or inappropriate adjustments with Photoshop's Shadow/Highlight tool.

What I have noticed is that HDR in PSCS2 is not able to recover highlights well. If the lowest exposure is a full exposure to the right, the highlights will be slightly blown. In order to avoid this, I think it's necessary to include an underexposed image when using HDR.

Loading 16 bit TIF conversions into HDR seems to produce some pretty awful results.
[a href=\"index.php?act=findpost&pid=127206\"][{POST_SNAPBACK}][/a]

May I have your RAW files to test them with my routine?

Some people have come to me with different HDR programs (like Photomatix) and after fiddling some time with them achieved similar results to pixel selection for blending. But usually HDR's tone mapping enforces local microcontrast keeping low the overall contrast, and this provides very unreal results; it's simply a different concept. I prefer not to alter local nor overall contrast and let the user the task to get the best from the noise free image in the way he likes best (contrast curves, zone edition, even HDR on other sofware,...).
« Last Edit: July 09, 2007, 04:10:04 AM by GLuijk »
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Ray

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« Reply #82 on: July 09, 2007, 09:03:37 AM »

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May I have your RAW files to test them with my routine?

Some people have come to me with different HDR programs (like Photomatix) and after fiddling some time with them achieved similar results to pixel selection for blending. But usually HDR's tone mapping enforces local microcontrast keeping low the overall contrast, and this provides very unreal results; it's simply a different concept. I prefer not to alter local nor overall contrast and let the user the task to get the best from the noise free image in the way he likes best (contrast curves, zone edition, even HDR on other sofware,...).
[a href=\"index.php?act=findpost&pid=127226\"][{POST_SNAPBACK}][/a]

Sending the files right now. Hope my connection is not interrupted. In the meantime, here's the comparison between an HDR result and the lowest exposure converted in ACR with minus 1 EC.

These are actually 'print screen' crops of 200% enlargements. No processing has been done except adjusting the WB slider in the HDR shot for maximum highlight recovery.

[attachment=2782:attachment]

ps. Sorry about that water pipe in front of the view. It's manadatory in Nepal to always obstruct a fine view, if possible. Fortunately, there are still lots of pristine views they have not got around to spoiling yet   .
« Last Edit: July 09, 2007, 09:08:31 AM by Ray »
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vjbelle

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« Reply #83 on: July 09, 2007, 05:43:27 PM »

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Hmm, that seems useful, although it seems to require quite a few exposures to achieve that usefulness.

The requirement for the extended version of CS3 is also a bit bothersome; Adobe doesn't appear to provide an upgrade from CS3 to CS3 Extended.
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jani,

There is an upgrade path from CS3 to CS3 Extended.  I did just that today and I was way outside of the 30 day exchange time period.  It is important that your original purchase of CS3 was in fact an upgrade from an earlier PS release and not a purchase of the retail program.  Adobe sales is not completely familiar with this program but customer support aided me with their internal documentation that allows a customer who upgraded to CS3 and then would like to upgrade to CS3 extended the opportunity to receive full credit for their purchase and pay just the difference for CS3 Extended.  Contact customer support and they should be able to guide you through the process.

Hope this helps.....  

Victor
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Erick Boileau

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« Reply #84 on: July 11, 2007, 10:58:21 AM »

GLuijk   I like very much your concept to work directly in the RAW
I am using blending options since a long time  , or photomatix, but to do that directly in the RAW wil be the best
« Last Edit: July 11, 2007, 11:30:34 AM by erickb »
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MichaelEzra

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« Reply #85 on: July 16, 2007, 01:58:20 PM »

GLuijk,

When do you plan to release the new version of the program? It is very interesting!

Thanks,
« Last Edit: July 16, 2007, 01:58:34 PM by MichaelEzra »
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Wayne Fox

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« Reply #86 on: July 19, 2007, 11:26:53 PM »

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You are really reinventing the wheel here. Blending together the best parts of frames shot with different exposure levels has been around several years prior to HDR blending being added to Photoshop as a feature. I've been doing so since 2001 or so when I got my first digital camera.

In a way, yes, but in a way no.  What is normally talked about is blending multiple exposures to extend dynamic range.

This seems more of a technique to use 2 exposures of a scene that falls within the dynamic range of the sensor but pushes it to the limit to reduce noise in the shadow areas.

Granted the way to accomplish this is virtually identical.  Just most of us wouldn't bother doing this if our histogram shows we aren't clipping either shadows and highlights.

It has given me some food for thought however, and I can see now there are times doing this may be useful even if I'm not after an HDR image.

Guillermo Luijk

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« Reply #87 on: July 22, 2007, 10:31:54 PM »

I tested this technique as a regular technique in a photographic indoor session last week, but in high constrast scenes as windows opened outdoor. The result has been very good: easy shooting (just regular shot plus one +4EV additional shot for every scene), easy edition (just a curve on which I set a mask not to blow windows facing outside), and natural result with no noise and expanded dynamic range.

Find here some examples (Canon EOS 350D + Canon 10-22 and a really bad tripod):


















Taking the first scene: the 350D is too noisy to record outdoor highlights and indoor texture detail in a single shot. This happened when trying: highlights blown if texture is kept (picture left), texture is gone if highlights are kept (picture right):



Blending result:

« Last Edit: July 22, 2007, 10:37:46 PM by GLuijk »
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haefnerphoto

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« Reply #88 on: July 22, 2007, 10:43:49 PM »

What did you do to blend the exposures?  You mentioned a mask, how did you make it?  Jim

Guillermo Luijk

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« Reply #89 on: July 22, 2007, 11:06:18 PM »

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What did you do to blend the exposures?  You mentioned a mask, how did you make it?  Jim
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I used a little program I wrote to automate it, the download site must be somewhere in this thread.
The mask was just in the edition stage, to preserve the windows from blowing.
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button

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« Reply #90 on: July 23, 2007, 10:23:58 PM »

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GLuijk,

When do you plan to release the new version of the program? It is very interesting!

Yes, please let us know when the GUI version is available.  Your work is outstanding!

John
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Ray

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« Reply #91 on: July 24, 2007, 02:34:18 AM »

Indeed! Your interiors are very esthetic, GLuijk. Sorry I haven't got around to sorting it out with my ISP about the errors I get when I try to send you 12mb file files.

I should (could) be on broadband, but I object to signing a 24 month contract when I intend travelling a lot in the near future.
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Guillermo Luijk

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« Reply #92 on: July 25, 2007, 02:44:27 PM »

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I should (could) be on broadband, but I object to signing a 24 month contract when I intend travelling a lot in the near future.
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why don't you put your raw files on a pendrive and try someone else's fast connection?
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MichaelEzra

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« Reply #93 on: July 25, 2007, 04:55:01 PM »

GLuijk,

my complements to your work on this new tool.

I am curious, whether you adjust the alignment of images while merging them together? There is "HDR alignment tool" which can curently do that, and probably  could be used to provide input files to your program, yet not in the RAW format...

If you need any help with specific RAW files, I can offer Fuji S3 and Mamiya ZD files for testing.

Please let me know,

Thanks,

Guillermo Luijk

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« Reply #94 on: August 08, 2007, 06:54:14 AM »

Hi, for all those that could be interested, I have just uploaded an English version of the article explaining this technique: ZERO NOISE PHOTOGRAPHY

Hopefully I will write a final version of the program ready to use along this month (Aug 2007).

Regards
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Caracalla

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« Reply #95 on: August 08, 2007, 07:12:53 AM »

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Hi, for all those that could be interested, I have just uploaded an English version of the article explaining this technique: ZERO NOISE PHOTOGRAPHY

Hopefully I will write a final version of the program ready to use along this month (Aug 2007).

Regards
[a href=\"index.php?act=findpost&pid=132099\"][{POST_SNAPBACK}][/a]

[span style=\'font-size:14pt;line-height:100%\']Amazing tool[/span]

Looking forward to it!!!
Thanks
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feppe

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« Reply #96 on: August 08, 2007, 12:10:03 PM »

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Hi, for all those that could be interested, I have just uploaded an English version of the article explaining this technique: ZERO NOISE PHOTOGRAPHY

Hopefully I will write a final version of the program ready to use along this month (Aug 2007).

Regards
[a href=\"index.php?act=findpost&pid=132099\"][{POST_SNAPBACK}][/a]

Thanks! The latest examples you provide are most impressive, no haloing or artificial/painterly look usually connected to "true" HDR images. I look forward to your program!

MichaelEzra

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« Reply #97 on: August 20, 2007, 02:43:21 PM »

Any update on this?

Quentin

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« Reply #98 on: August 21, 2007, 12:12:33 PM »

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Any update on this?
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Looks great.  Charge a reasonable fee for a decent GUI based Windows program and I'll pay up  

Quentin
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Quentin Bargate, ARPS, Author, Arbitrator, Photographer and senior partner of Bargate Murray, the award winning Luxury Asset Law Firm

julian_love

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« Reply #99 on: August 22, 2007, 08:44:13 AM »

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Looks great.  Charge a reasonable fee for a decent GUI based Windows program and I'll pay up   

Quentin
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Me too, for a Mac version.

Julian
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